Surface Morphology Evolution Mechanisms of InGaN/GaN Multiple Quantum Wells with Mixture N2/H2-Grown GaN Barrier

This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Surface morphology evolution mechanisms of InGaN/GaN multiple quantum wells (MQWs) during GaN barrier growth with different hydrogen (H2) percentages have been systematically studied. Ga surface-diffusion rate, stress relaxation, and H2 etching effect are found to be the main affecting factors of the surface evolution. As the percentage of H2 increases from 0 to 6.25%, Ga surface-diffusion rate and the etch effect are gradually enhanced, which is beneficial to obtaining a smooth surface with low pits density. As the H2 proportion further increases, stress relaxation and H2 over- etching effect begin to be the dominant factors, which degrade surface quality. Furthermore, the effects of surface evolution on the interface and optical properties of InGaN/GaN MQWs are also profoundly discussed. The comprehensive study on the surface evolution mechanisms herein provides both technical and theoretical support for the fabrication of high-quality InGaN/GaN heterostructures.Peer reviewe

Quantifying Bus Accessibility and Mobility for Urban Branches: A Reliability Modeling Approach

In order to quantitatively assess the realization degree of urban branch road function, an evaluation method based on reliability theory was established. Firstly, the main characteristics of urban branch road functions, that is, emphasizing accessibility while maintaining mobility, were analyzed. Based on common road network patterns, the branch road network between adjacent higher-level roads was selected as the research object. Public transportation, which is more representative of accessibility, was considered in the evaluation method. Then, a reliability model for branch road function evaluation was proposed, in which walking distance and travel time by bus were taken as the main indicators. Combining Dijkstra algorithm and Monte Carlo simulation, the model was solved. The feasibility of the method was verified through a case study of two branch road units. Then, influences of road network density, connectivity, and bus route layout on the reliability of branch road unit functions were clarified by sensitivity analysis. Results showed that the reliability of the branch unit exhibited a trend of initially increasing and then decreasing with the growth of road network density and connectivity, which indicated that excessively high road network density may hinder the performance of the branch road unit. Adjusting the layout of bus routes within branch road units and expanding the service area of bus routes can enhance reliability. Finally, some suggestions for optimizing branch road unit reliability were provided

Secrecy and Throughput Performance of Cooperative Cognitive Decode-and-Forward Relaying Vehicular Networks with Direct Links and Poisson Distributed Eavesdroppers

Cooperative communication and cognitive radio can effectively improve spectrum utilization, coverage range, and system throughput of vehicular networks, whereas they also incur several security issues and wiretapping attacks. Thus, security and threat detection are vitally important for such networks. This paper investigates the secrecy and throughput performance of an underlay cooperative cognitive vehicular network, where a pair of secondary vehicles communicate through a direct link and the assistance of a decode-and-forward (DF) secondary relay in the presence of Poisson-distributed colluding eavesdroppers and under an interference constraint set by the primary receiver. Considering mixed Rayleigh and double-Rayleigh fading channels, we design a realistic relaying transmission scheme and derive the closed-form expressions of secrecy and throughput performance, such as the secrecy outage probability (SOP), the connection outage probability (COP), the secrecy and connection outage probability (SCOP), and the overall secrecy throughput, for traditional and proposed schemes, respectively. An asymptotic analysis is further presented in the high signal-to-noise ratio (SNR) regime. Numerical results illustrate the impacts of network parameters on secrecy and throughput and reveal that the advantages of the proposed scheme are closely related to the channel gain of the relay link compared to the direct link

Trustworthy faces make people more risk-tolerant: The effect of facial trustworthiness on risk decision-making under gain and loss conditions

People can judge a stranger&#39;s trustworthiness at first glance solely based on facial appearance. Moreover, the trust behaviors people exhibit toward strangers differ depending on perceived trustworthiness from faces. Research has found that people have different risk preferences according to the gain or loss frame. Therefore, we hypothesized that the risk decisions are differently affected by facial trustworthiness in different frames. We conducted three experiments in which we asked participants to make risk decisions in the gain frame or loss frame. The results revealed that facial trustworthiness had a significant effect on risk decisions in the gain frame. However, the effect was attenuated in the loss frame. These results suggest that people are more willing to take risks in the gain frame if individuals look more trustworthy than those who look untrustworthy.</p

Spectral purification improves monitoring accuracy of the comprehensive growth evaluation index for film-mulched winter wheat

In order to further improve the utility of unmanned aerial vehicle (UAV) remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching, ridge–furrow full mulching, and flat cropping full mulching in winter wheat. Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV. Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks (ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out. The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status. The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75, a root mean square error of 8.40, and a mean absolute value error of 6.53. Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remote-sensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification. The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching

Combined tillage: A management strategy to improve rainfed maize tolerance to extreme events in northwestern China

Climate warming has increased the frequency of droughts and excessive precipitation, adversely affecting crop growth, particularly under traditional intensive tillage. No-till improves crop tolerance to extreme events by reducing soil evaporation and improving soil structural stability to enhance soil water storage capacity and crop resistance, but long-term mono-no-till cakes the soil, reducing crop yield. Combining intensive tillage with no-till can compensate for some deficiencies arising from conventional tillage or single no-till. A three-year field experiment was conducted in wet (2020) and normal (2019 and 2021, where a drought event occurred in 2021) years to study the effect of tillage practices on summer maize productivity under different precipitation types. Treatments included conventional tillage (CT), no-tillage (NT), ridge cultivation with no-tillage (RNT), and conventional tillage of winter wheat combined with no-tillage of summer maize (NC). Compared with NT, NC and RNT significantly reduced soil bulk density and increased soil porosity in the 0–20 cm soil layer. Compared with CT, NC and RNT significantly improved aggregate stability, NC increased available soil water storage by 19.7% in the dry season (P < 0.05), and NC and RNT significantly reduced lodging rate in the rainy season. Over the three years, NC and RNT maintained higher maize yields (NC: 10.3 t ha–1 and RNT: 10.0 t ha–1) than CT (9.2 t ha–1), and NC had significantly higher yield stability than CT. Meanwhile, NC and RNT had higher precipitation use efficiency (PUE; NC: 21.2 kg ha–1 mm–1, RNT: 20.7 kg ha–1 mm–1) than NT (20.1 kg ha–1 mm–1) or CT (19.1 kg ha–1 mm–1). In terms of combined productivity, NC and RNT provide a more suitable soil environment for crop growth and maintain higher yield than NT and CT. NC rotation is recommended as the optimal tillage system for sustainable crop production under semi - arid agricultural conditions. RNT can be extended to areas prone to flooding with abundant rainfall. These results offer a benchmark for future studies on regional maize production under climate change

Factors influencing parents’ willingness to vaccinate their preschool children against COVID-19: Results from the mixed-method study in China

During the COVID-19 pandemic, little is known about parental hesitancy to receive the COVID-19 vaccine for preschool children who are the potential vaccinated population in the future. The purpose of this mixed-method study was to explore the factors influencing Chinese parents’ decision to vaccinate their children aged 3–6 years old against COVID-19. In July 2021, we conducted semi-structured interviews (n = 19) and a cross-sectional survey (n = 2605) with parents of kindergarten children in an urban-rural combination pilot area in China. According to the qualitative study, most parents were hesitant to vaccinate their children with the COVID-19 vaccine. In the quantitative study, we found that three-fifths of 2605 participants were unwilling to vaccinate their children against COVID-19. Furthermore, the main predictors of parents’ intention to vaccinate their children were fathers, lower level of education, and positive attitudes toward vaccination. Based on our findings, targeted health education techniques may be able to boost childhood COVID-19 immunization rates

Synthesis, Biological Evaluation, and Molecular Modeling of Glycyrrhizin Derivatives as Potent High-Mobility Group Box‑1 Inhibitors with Anti-Heart-Failure Activity in Vivo

Novel glycyrrhizin (GL) derivatives were designed and synthesized by introducing various amine or amino acid residues into the carbohydrate chain and at C-30. Their inhibitory effects on high-mobility group box 1 (HMGB1) were evaluated using a cell-based lipopolysaccharide (LPS) induced tumor necrosis factor α (TNF-α) release study. Compounds <b>10</b>, <b>12</b>, <b>18</b>–<b>20</b>, <b>23</b>, and <b>24</b>, which had substituents introduced at C-30, demonstrated moderate HMGB1 inhibition with ED₅₀ values ranging from 337 to 141 μM, which are values comparable to that of the leading GL compound (<b>1</b>) (ED₅₀ = 70 μM). Compounds <b>23</b> and <b>24</b> emerged as novel and interesting HMGB1 inhibitors. These compounds were able to extend the survival of mice with chronic heart failure (CHF) and acute heart failure (AHF), respectively. In addition, molecular modeling studies were performed to support the biological data